RESUMEN
In many countries, HIV testing among tuberculosis (TB) patients is recommended so that both infections are appropriately treated. Cross-reacting antibodies to HIV antigens have been reported for several conditions, including TB, leprosy, malaria, and rheumatoid arthritis. To study the pattern and prevalence of cross-reacting antibodies to HIV antigens, we examined sera from 153 HIV-negative TB patients and 40 healthy individuals in Chennai, south India. We also studied the differences in cross-reactivity of various HIV antigens using two different Western blot kits. Of the 153 samples studied, 80 were tested using HIV Western blot and 73 were tested using INNOLIA. Most patients in the study had concordantly negative ELISA and rapid tests, and no subject had a positive Western blot. However, seven TB patients had antibodies that cross-reacted with HIV antigens, giving rise to an indeterminate result. While p51/55 was the most frequently recognized antigen in the Western blot assay, antibodies to sgp120 was most frequently identified in INNOLIA. Sequence similarities between the two organisms could be responsible for eliciting cross-reacting antibodies, since a few related epitopes were identified in HIV and Mycobacterium. These findings could have potential implications for the development of diagnostics and vaccines.
Asunto(s)
Anticuerpos Antibacterianos/sangre , Anticuerpos Antibacterianos/inmunología , Epítopos/genética , Antígenos VIH/inmunología , VIH/inmunología , Mycobacterium tuberculosis/inmunología , Tuberculosis/sangre , Western Blotting , Reacciones Cruzadas , Ensayo de Inmunoadsorción Enzimática , Antígenos VIH/genética , Proteína gp120 de Envoltorio del VIH/inmunología , Transcriptasa Inversa del VIH/inmunología , Humanos , Mycobacterium tuberculosis/genética , Precursores de Proteínas/inmunología , Juego de Reactivos para Diagnóstico , Análisis de Secuencia de ProteínaAsunto(s)
Antígenos Bacterianos/genética , Antígenos Bacterianos/inmunología , Antígenos Bacterianos/aislamiento & purificación , Clonación Molecular , Escherichia coli , Estadística como Asunto , Expresión Génica , Genes Bacterianos , /biosíntesis , Monocitos/inmunología , Mycobacterium leprae/genética , Mycobacterium leprae/inmunología , Mycobacterium leprae/aislamiento & purificación , Peso Molecular , Precursores de Proteínas/genética , Precursores de Proteínas/inmunología , Precursores de Proteínas/aislamiento & purificación , Proteínas Bacterianas/genética , Proteínas Bacterianas/inmunología , Proteínas Bacterianas/aislamiento & purificaciónRESUMEN
A novel Mycobacterium leprae lipoprotein LpK (accession no. ML0603) was identified from the genomic database. The 1,116-bp open reading frame encodes a 371-amino-acid precursor protein with an N-terminal signal sequence and a consensus motif for lipid conjugation. Expression of the protein, LpK, in Escherichia coli revealed a 33-kDa protein, and metabolic labeling experiments and globomycin treatment proved that the protein was lipidated. Fractionation of M. leprae demonstrated that this lipoprotein was a membrane protein of M. leprae. The purified lipoprotein was found to induce production of interleukin-12 in human peripheral blood monocytes. The studies imply that M. leprae LpK is involved in protective immunity against leprosy and may be a candidate for vaccine design.